Effects of response format on achievement and aptitude assessment results: multi-level random effects meta-analyses.

Psychological achievement and aptitude tests are fundamental elements of the everyday school, academic and professional lives of students, instructors, job applicants, researchers and policymakers. In line with growing demands for fair psychological assessment tools, we aimed to identify psychometric features of tests, test situations and test-taker characteristics that may contribute to the emergence of test bias. Multi-level random effects meta-analyses were conducted to estimate mean effect sizes for differences and relations between scores from achievement or aptitude measures with open-ended (OE) versus closed-ended (CE) response formats. Results from 102 primary studies with 392 effect sizes revealed positive relations between CE and OE assessments (mean r = 0.67, 95% CI [0.57; 0.76]), with negative pooled effect sizes for the difference between the two response formats (mean d av = -0.65; 95% CI [-0.78; -0.53]). Significantly higher scores were obtained on CE exams. Stem-equivalency of items, low-stakes test situations, written short answer OE question types, studies conducted outside the United States and before the year 2000, and test-takers' achievement motivation and sex were at least partially associated with smaller differences and/or larger relations between scores from OE and CE formats. Limitations and the results' implications for practitioners in achievement and aptitude testing are discussed.

Iron (hydr)oxide formation in Andosols under extreme climate conditions.

Redox-driven biogeochemical cycling of iron plays an integral role in the complex process network of ecosystems, such as carbon cycling, the fate of nutrients and greenhouse gas emissions. We investigate Fe-(hydr)oxide (trans)formation pathways from rhyolitic tephra in acidic topsoils of South Patagonian Andosols to evaluate the ecological relevance of terrestrial iron cycling for this sensitive fjord ecosystem. Using bulk geochemical analyses combined with micrometer-scale-measurements on individual soil aggregates and tephra pumice, we document biotic and abiotic pathways of Fe released from the glassy tephra matrix and titanomagnetite phenocrysts. During successive redox cycles that are controlled by frequent hydrological perturbations under hyper-humid climate, (trans)formations of ferrihydrite-organic matter coprecipitates, maghemite and hematite are closely linked to tephra weathering and organic matter turnover. These Fe-(hydr)oxides nucleate after glass dissolution and complexation with organic ligands, through maghemitization or dissolution-(re)crystallization processes from metastable precursors. Ultimately, hematite represents the most thermodynamically stable Fe-(hydr)oxide formed under these conditions and physically accumulates at redox interfaces, whereas the ferrihydrite coprecipitates represent a so far underappreciated terrestrial source of bio-available iron for fjord bioproductivity. The insights into Fe-(hydr)oxide (trans)formation in Andosols have implications for a better understanding of biogeochemical cycling of iron in this unique Patagonian fjord ecosystem.